1. Field of the Invention
This invention relates to an environmentally recycling-oriented bio-liquid crystal polymer made from a tissue-derived product or the derivatives and, particularly, to a bio-liquid crystal polymer available in wide fields such as medical apparatus, electronic and electrical parts and automobile parts.
2. Description of the Related Art
Conventional liquid crystal polymers are of lyotropic type to be processed while being dissolved by solvents and thermotropic type to be thermally processed. The lyotropic type includes aromatic polyamides and polyphenylenebisbenzothiazol, and the thermotropic type includes polyesters (aromatic diols, aromatic dicarboxylates, hydroxycarboxylates). The liquid crystal polymers have a high mechanical strength and, therefore, the polymers can be used for electronic and electrical parts.
However, the polymers belong to environmentally accumulated type that is difficult to decompose and, thus, is accumulated in the environment. Therefore, polymers that belong to environmentally recycling-oriented type are desired since they are easily decomposed to give only water and carbon dioxide and, thus, do not affect the environment.
Doi Yoshiharu, “Biodegradable Plastic Handbook”, first edition, pages 576–581, NTS Co. Ltd., May 26, 1995 reports an example of the environmentally recycling-oriented polymer, polylactic acid. The polylactic acid is made from the starch of corns or potatoes. When disposed, it is subject to hydrolysis or biodegradation to give water and carbon dioxide. The polylactic acid can be used for agricultural film, disposal container and stationery.
However, the polylactic acid polymers has a thermal deformation temperature as low as about 60° C. and, therefore, it cannot be used for products requiring a high thermal resistance such as automobile parts.